To be fair, you’re covered with the primary signal if the local drunks decide to partake of a bit souvenir gathering… but for the sake of a bit of thermo, I’d be inclined just to slap some lines down anyway. Should only be a few quid!

Personally, if I knew they were going to be in for that long I would have put the stop lines in when they were first erected. That said, how much life have they got left?

TSRGD says:

“(3) Where no stop line has been provided in conjunction with light signals or the stop line is not visible, references in relation to those signals to the “stop line” are:

(a) in a case where the sign shown in diagram 7011, 7011.1, 7011.2 or 7027 is placed in conjunction with the light signals, to be treated as references to that sign; and

(b) in any other case, to be treated as references to the post or other structure on which the primary signals are mounted.”

… so you’re covered with the signs.